Control of polyphase electromotors



7' P. H. STEVENS CONTROL OF POLYPHASE ELECTROMOIORS Filed Aug. 5. 1925 5 Sheets-Sheet 1 P. H. STEVENS CONTROL OF POLYPHASE ELECTROMOTORS Filed Aug. 5 1925 s Sheets-Sheet 2 P. H. STEVENS CONTROL OF POLYPHASE ELECTROMOTORS Fild Aug. 5, 1925 3 Sheets-Sheet 3 Patented 0ct.18, 1927.

UNITE-D STATES.

PERCY HERBERT s'rnvnns, or NORTHAMPTON, ENGLAND, assrenon T0 sivr rrrr,

, 1,645,827 Parent OFFICE.

MAJOR 8a STEVENS LIM1TED,OF ABBEY WGBKS, NORTHAMPTON, ENGLAND.

CONTROL OF POLYPHASE ELECTROMOTOR S'.

Application filed August 3, .1925, Serial No. 47,887, and in Great Britain August 1924,

This invention relates to means for controlling the speed of polyphase electromotors, and is especially adapted for use where polyphase motors having commutator brushes are employedfor operating lifts and in which it is desirable to control the speed 'ofthe motor from the lift. cage, so as to increase the speed after the cage has started and to restore the speed to normal; as the floor where the stopping is to take place, is approached. r V

Polyphase motorsof the type referred to have already been fitted with means for.adjusting their speed. One such arrangement consists of means for rocking the commutator brushes and thus increasing the speed of the motor, and by rocking the brushes back to their normal position the normal speed may again be resumed.

In some cases the brushes are arranged in two sets relatively to one another so as to rock in opposite directions simultaneously, the said brushes being in such a construction carried on rocker rings concentric to the motor shaft and being moved equally inopposite directions by means of spur gearing. The rotation of such gearing in one direction gives both rocker rings angular movement from the normal position, one in a clockwise direction and the other in a counter-clockwise direction, and the reversing of the spur gearing allows thetwo sets of brushes to be returned to the normal position where the normal speed of the motor is resumed.

Hitherto the rocking of the rocker rings for speed adjustment has been achieved either by hand or by means of an independent pilot motor.

Now the object of the present invention is to construct means for adjusting commutator brushes by the mere operation of clutch mechanism which, on being brought into ac tion, enables movement to be transmitted from amoving part of the lift mechanism to the control mechanism for adjusting the position of the brushes. The clutch referred to is operated from the lift cage to open and close electrically, in such a manner that on the clutch being operated, some moving part of the lift, such for instance as the drum shaft, is caused to operate the change mechanism and to move such part or parts of the polyphase motor as to cause the brushes to be moved in their proper relationship and thus increase the speed of the motor; whilst '7 control mechanismthe lift may'travel slowly to its destination and the current may be cut off from the motor in the present way;

or after the lift has been started under normal conditions, it may then be accelerated by the operator introducing the clutch mechanism which effects the adjustment of the brushes, and the increased speedis added smoothly by the operation of the lift winding gear. The maximum speed maybe continued until the operator cuts out the clutch and thus returns the motor to its normal speed immediately prior to finally cutting off the current from the motor in order to stop accurately and smoothly at the predetermined floor level. Y

In the accompanying drawings, examples of construction of mechanism according to this invention are illustrated, Figure l bein a plan view of a clutch mechanism an means for moving the brush rocker rings. Figure 2 is an elevation of the clutch mechanism, and Figure 3 an elevation showing means for moving the rocker rings. Figures 4 and 5 are front and side elevations showing a modification of the means for moving the rocker rings, and Figure 6 shows a further modification. Fig. 7 diagrammaticallyillustrates the driving motor, brush shifting means, the clutch, the connection betweenthe clutchand the lift and the electric circuit for the clutch.

Referring particularly toFigures 1, 2 and 3 of the drawings. a shaft A carries a spur wheel B which engages with arack formed on one of the brush rocker rings C,and the other brush rocker ring C which requires to be adjusted in the opposite direction, gears with an intermediate spur wheel 0 and thence to a spur wheel B on the shaft A. This shaft also carries a drum D to which three chains are connected. One of these chains E carries a weight E which tends to move and to retain the shaft A in the-position where,,through the spur gearing,

I The other two chains F, F passover the, of the chain drum and extend to the the rocker rings hold the brushes for the motor when running at the lowest speed.

top clutch drum G, one of the chains F being attached to the upper side of the clutch side of the said drum. Thus, by the clutch drum rotating clockwise or anti-clockwise,

one or "other of the chains is pulled, and the 'chainfld'rum on the first-mentioned shaft is rotated in one direction regardless of the 'direction of rotation of the clutch drum.

The clutch drum G is carried on some moving part of the lift mechanism, and preferably on the lift shaft, so that on the clutch being actuated either during the ascent or descent of the'lift, one or other of the chains F, F} is pulled and the brush rocker rings C moved with their brushes,

"a d thus thespeed of the motor is accelerated. V

The clutch operating the clutch drum G is operated magnetically by a current received from the lift cage. All the time this auxiliary or shunt current is passing, the

clutch is operated sufficiently to continue to move the rocker rings C in opposite directions, so as to adjust the brushes until the maximum speed is reached, when the clutch may be permitted to slip and yet retain,

through the chain connection F, F and gear,

normal position, and the speed of the motor is reducedto'its normal rate.-

Referring particularly to Figures 4 and 5,which show both rocker rings C and C carrying commutator brushes C bearing upon the commutator C of the motor, the

brush rocker rings are carried in a frame C which is provided with anti-friction rollers arms (3 ,0

"WGIghlZS E and the arms C are connected C entering grooves in the peripheries of the rocker rings; Brackets C are attached to the rocker rings and extend outside the frame C and carry outwardly extending To the arms C are attached by chains or rods H to levers J rigidly mounted on a shaft K which is mounted in bearings in the main frame of the motor.

7 Chains F and F attached to the upper and under side of the drum D are connected at their opposite ends with a lever L also fast on the shaft K. Upon the clutch being actuated,the drum D will be revolved, and through one or other of the chains F, F according to which direction the drum D is rotated, the lever L will be pulled and rock the shaft K, and through levers J and chains and the second chain F to the under reached and the clutch is permitted to slip and yet retain the lugs C in contact with the stop M. Upon the disengagement of the clutch mechanism, the weightsE? will vmove the rocker rings back to their original position, and the lugs C will contact with the stops M.

Figure 6 shows an arrangement. of mechanism, whereby one weight E w1ll return both the rocker rings to their original position'after they have been revolved. As

shown'in'this figure, thelevers J mounted on thejshaft Kare connected to the rocker rings C, O by rods H, and a lever .N also fixed to the shaft K carries the weight E and thespeed at which the weight returns the rocker rings from the high speed to the low speed position is controlled-by means'of a dash-pot O. A dash-pot could of course be applied to control the speed of the return movement of the brushes in any arrangements to which the invention is applied.

Referring to the diagram Fig. 7 a control lever P, which is conveniently mounted on the lift cage, may be rocked to right or left according to the direction, up or down,

required for the lift. WVhen the lever P is rocked to'the position shown in dotted lines, the lift starts in an upward direction and travels at its minimum speed. Upon the operator rocking the control lever -P further to the left, a shunt or auxiliary current passes to the-solenoid Q, which moves the solenoidcore, thus operating the clutch andcausing the drum G to be gripped to the shaft G which is driven from the lift shaft R, pulling the chains F or F rocking the lever J and pulling down the rods H, thus rockingthe brush rocker rings C, C through the medium of the arms C and brackets C and progressively increasing the speed of the, lift.

The operator, before reaching his destination, brings the lever P again to the dotted line position whereby the clutch drum G is freed from the shaft G and the. brush rocker rings C, C are returned to their normal positions bythe weights E E The lift thus slows down to its minimum speed prior to the current being cut off from the motor by bringing the lever P to its final central position when the lift arrives.-

lVhat I claim as my invention and desire to secure by Letters Patent is 1. In association with a lift having a rotary part and operated by a polyphase motor having a commutator and commutator brushes the combination of a clutch having for a driving and a driven part, means for advancing the commutator brushes adapted to I clutch and the rotary part of the lift mechanism, electric means for operating the clutch, means for completmg and breaking the electric c1rcu1t operating the clutch and means for returningthe brushes to the initial position when the circuit is broken.

2. In association with a lift having a. rotary part and operated by a polyphase motor having a commutator and "commutator brushes the combination of a clutch having a driving and a driven part, means for advancing the commutator brushesadapted to be operated by the driven part of the clutch, a shaft permanently in rotary connection with the rotary part of the lift mechanism and carrying the driving part of the clutch, electric means for operating the clutch, means for completing and breaking the electric circuit operating the clutch and means for returning the brushes to the initial position when the circuit is broken.

3. In association with a lift having a rotary part and operated by a polyphase motor having a commutator and commutator brushes the combination of a clutch having a driving and a driven part, means advancing the commutator brushes adapted to be operated by the driven part of the clutch, a shaft permanently in rotary connection with the rotary part of the lift mechanism and carrying the driving part of the clutch, a solenoid core, a mechanical connection operatively connecting the solenoid core with the clutch, an electrical circut for energizing the solenoid, means for completing and breaking the electric circuit for the solenoid and means for returning the brushes to the initial position when the circuit is broken.

4. In association with a lift having a rotary part and operated by a polyphase motor having a commutator and commutator brushes, the combination of a clutch having a driving and a driven part, means for advancing the commutator brushes adapted to be operated by the driven part of the clutch, a shaft permanently in rotary connection with the rotary part of the lift mechanism and carrying the driving part of the clutch, a solenoid core, a mechanical connection operatively connecting the solenoid core with the clutch, an electric circuit for energizing the solenoid, means for completing and breaking the electric circuit of the solenoid and weights operatively connected with the commutator brushes adapted to return the brushes to their initial position on breaking the electric circuit.

5. In association with a lift having a rotary part and operated by a polyphase motor having a commutator and commutator brushes, the combination of two brush rocker rmgs carrying the commutator brushes of the motor, a clutch having a driving anda driven part; a rotary member operated by the 'driven part or the clutch,

means operativelyv connecting the rotary partof the lift mechanism with the driving part of the clutch, a rockershaft,two levers on the rocker shaft, couplings connecting said levers to the brush rings, a third lever on the rocker shaft, operative connections betweenthe third lever andopposite sides of the rotaryme'mbe'r operated by the driven side of the clutch, electric means for operating the, clutch, means for completing and breaking the electric circuit operating the clutch and means for returning the brushes tofthe initial position when the circuit is broken.

V 6. In association with a lift having a rotary part and operated by a. polyphase motor having a commutator and commutator brushes, the combination of two brush rocker rings carrying the commutator brushes of the motor, a. clutch having a driving and a driven part, a rotary member operated by the driven part of the clutch, means operatively connecting the, rotary part of the lift mechanism with the driving part of the clutch, a rocker shaft, two levers on the rocker shaft, couplings connecting said leversto the brush rings, a third lever on the rocker shaft, operative connections between the third lever and opposite sides of the rotary member operated by the driven side of the clutch, an arm on the rocker shaft, a weight pendent from the arm adapt- I ed to return the rocker shaft to normal position, electric means for operating the clutch andmeans for completing and breaking the electric circuit. v

7. In association with a lift having a rotary part and operated by a polyphase motor having a commutator and commutator brushes, the combination of two brush rocker rings carrying the commutator brushes of the motor, a clutch having a driving and a driven part, a rotary member operated by the driven part of the clutch, means oper atively connecting the rotary part of the lift with the driving part of the clutch, a rocker shaft, two levers on the rocker shaft, couplings connecting said levers with the brush rings, a third lever on the rocker shaft, operative connections between the third lever and opposite sides of the rotary member operated by the driven part of the clutch, electric means for operating the clutch, means for completing and breaking the electric circuit, means for returning the brushes to the initial position when the circuit is broken and a dash-pot to control the speed of the return movement of the rocker rings.

8., association With a lift having a roa clutch having a driving and a driven part,

a rotary member operated by the driven part of the clutch, means operatively connecting the rotary part of the lift with, the

driving part of the clutch, lugs on' the brush rocker rings, stops on the frame of the motor with which the lugs engage to limit the movement of the rocker rings, a

rocker sha;ft, 1ever arms on the rocker shaft,

' mew rods connecting the rocker rings with the lever arms of the rocker shaft, a third lever on the rocker shaft, means operatively connecting the third leverwith opposite sides of the rotary member operated by the driven part of the clutch, electric meanstor operating the clutch, means for completing and breaking the electric circuit, and means for returning the brushes to the initialposition vvhen the circuit is broken.

In Witness whereof I have hereunto set my hand.

'"PERGY HERBERT STEVENS. 

